The present invention relates to a disk array apparatus, a data migration method, and a storage medium, and is preferably applied to, for example, a storage system for migrating data between a plurality of disk array apparatuses.
Because of an explosive increase in the use of data by companies in recent years, storage systems that store large volumes of data by mutually connecting a plurality of disk array apparatuses via, for example, a SAN (Storage Area Network) have come into wide use.
In such storage systems, an information processor for managing a plurality of disk array apparatuses is used to optimize data arrangement in each disk array apparatus.
As a storage system for optimizing data arrangement, JP-A-2003-140836, for example, suggests a storage system that has an information processor acquire manufacturer information and usage-state information for each disk array apparatus, and migrates data between storage areas in the individual disk array apparatuses and between storage areas in the respective disk array apparatuses, based on the manufacturer information and the usage-state information.
Lately the concept of Data Lifecycle Management (DLCM) has been proposed in the field of storage systems. The concept of DLCM is to retain and manage data efficiently by focusing attention on the fact that the value of data changes over time.
In the DLCM, for example, storing data of diminished value in expensive storage devices is a waste of storage resources. Accordingly, such data with diminished value is migrated to inexpensive storage devices that are inferior to other, expensive storage devices in reliability, responsiveness, and durability.
If in such a storage system the data stored in storage areas in expensive storage devices are migrated to inexpensive storage devices at designated dates and times at regular intervals, for example, every week or every month, ideally the data migration is completed at that designated date and time as much as possible.
However, in order to terminate the data migration at the designated date and time, there is the problem of difficulty in estimating migration start time due to factors such as a transfer speed during the data migration. As a result, it is difficult to terminate the data migration at the designated time.
Since it is difficult to terminate the data migration at the designated time as described above, a user has to estimate the migration termination time and set the migration start time, making the required operation cumbersome and complicated. At the same time, assuming the possibility of the termination of data migration failing, a user needs to prepare spare storage areas in expensive storage devices. Therefore, there is a problem in that the expensive storage devices cannot be used efficiently.